Engineering redox-active benzo[1,2-b:4,5-b']dithiophene-based conjugated polymers: tuning porosity and linker architecture for high-performance supercapacitors

Abstract

Conjugated polymers emerge as promising candidates for next-generation supercapacitor electrodes due to their high conductivity, redox activity, and π-conjugated frameworks. In this work, we conduct a comprehensive investigation into how porosity and linker architecture affect the electrochemical properties of four conjugated polymers that incorporate the redox-active benzo[1,2-b:4,5-b']dithiophene-4,8-dione (DTDO) units. Specifically, two types of porous polymers (Ph-DTDO porous and TEPh-DTDO porous) and two types of linear polymers (Ph-DTDO linear and DEPh-DTDO linear) are synthesized using Suzuki and Sonogashira coupling reactions, employing structurally tailored phenyl-based linkers. Among them, Ph-DTDO porous conjugated polymer demonstrates superior performance, delivering a high specific capacitance of 842.4 F g‒1 at 0.5 A g‒1 and excellent stability with 98.78% retention after 6000 cycles in a three-electrode system. Furthermore, the symmetric supercapacitor device assembled with Ph-DTDO porous polymer exhibits an energy density of 59.4 Wh kg‒1 and a specific capacitance of 428.21 F g‒1. Comparative analysis reveals that the porous architecture and phenyl-bridged linker facilitate enhanced ion diffusion, higher capacitive contribution, lower charge transfer resistance, and improved π-π stacking interactions, thus significantly boosting the energy storage capabilities. This work underscores the crucial role of structural engineering in conjugated polymers and offers valuable design insights for high-performance energy storage materials.